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What is light pollution ? What is light pollution ? Light pollution is the unnecessary waste of light in large cities, and is a direct consequence of poorly designed public lighting. Although it isnt considered as harmful as conventional pollution (smog, CO 2, waste), light pollution can cause sleep disorders, disorient migratory animals, destroy floral ecosystems and even increase the risk of cancer in humans, and last but not least, it drastically decreases the effectiveness of telescopes. Over cities, the halo effect appears – an orange mist. In Europe, for example, this halo increases by 5% a year and blocks 90% of visible stars to the naked eye.

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In Bucharest, due to the obsolete design of the public and private lighting lamps, or because of how they are mounted on poles, more than 30% of the light produced is directed above the horizontal, resulting in the halo effect. Thus Romanians end up paying about 700 thousand RON per year on light lost in the sky which prevents astronomers to observe the stars accordingly. In Bucharest, due to the obsolete design of the public and private lighting lamps, or because of how they are mounted on poles, more than 30% of the light produced is directed above the horizontal, resulting in the halo effect. Thus Romanians end up paying about 700 thousand RON per year on light lost in the sky which prevents astronomers to observe the stars accordingly.

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In February 2000, the Directorate General for Energy and Transport (DG TREN) of the European Commission launched the GreenLight project for the promotion of advanced, clean, lighting systems, to protect the purity of the night sky. Also, countries such as Spain or Italy have put into practice their own laws restricting harmful effects of artificial night lighting: In 1992, Italy issued a special ordinance to protect the activity of astronomical observatories. In February 2000, the Directorate General for Energy and Transport (DG TREN) of the European Commission launched the GreenLight project for the promotion of advanced, clean, lighting systems, to protect the purity of the night sky. Also, countries such as Spain or Italy have put into practice their own laws restricting harmful effects of artificial night lighting: In 1992, Italy issued a special ordinance to protect the activity of astronomical observatories.

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As a solution to this problem, in America, the International Association "Dark-Sky" has requested that incandescent light bulbs used for public lighting (efficiency is 8 ~ 25 lumens / watt) to be exchanged with LSP bulbs (low-pressure sodium ) or HPS (high- pressure sodium) which have a much higher efficiency (90 ~ 200 lumens / watt) and emit mainly just a single wave of light that can be easily filtered by telescopes. Slowly, governments have begun to make these changes to reduce the energy consumption of the world, in these times of ecological consciousness. The Team : Diaconescu Vladimir Pantazi I. Victor Pop Ioan Andrei Ţogui Vlad Bibliography : http://astroclubul.tripod.com/romanian/poluare.html http://www.ecomagazin.ro/poluarea-luminoasa-stinge-stralucirea-stelelor http://astroclubul.tripod.com/romanian/poluare.html Some Pictures from Flickr: http://www2.arnes.si/~sssknm2/anglesko/indeks.htm http://www2.arnes.si/~sssknm2/anglesko/indeks.htm